VO TRQNG HUNG Truxmg Dai hgc Mo-Dia chat ngim Idn can, mat dit, cdc cdng trinh xdy dyng tren mat ddt,...; • Dam bao cdc Id min phai dupc bo tri deu ddn, hpp ly tren toan bO gu'ang thi c
Trang 1_ ^ ^
NGHIEN CUU XAC DjNH SO LUffNG
vn PHirONG PHRP BO TRI CflC L 6 MJN HOP LV TRCN
GirONG T H I CONG CONG T R I N H NGAM
—^ au khi x^c ^nh s6 lu-grig 16 min, ngii-b-i thiet k l
^ 7 d n tiln h§nh bo tri cac 16 min tren gifcng thi
^ ^ c6ng cong trinh ng§m Vi^c xSc 5jnh s6 lu'p'ng
vd phifo'ng phdp b6 tri c§c lo min tren gu'O'ng phai
dam bao cdc ySu c3u va hi^u qua cho cdng tdc
khoan n6 min S6 lu'p'ng va phu-ong phap b6 tri cdc
l6 min trSn gu-ang la nhu'ng tiiong so khoannS min
quan trpng khi thiet ke cong ngh# thi c6ng c6ng trinh
ngam Tuy nhifin, cho d i n nay cdc th6ng so ky thuat
ndy Vdn chu-a du'p'c xdy dp'ng mOt cdch chuan xdc
Nhi^u chl dan trong cdc tai li$u thiet k l ky thu^t v l
vin d l ndy van mang tinh djnh tinh Nhilu ludn dilm
con rit ma h i Vi vay, vi^c nghien cO-u xdy dyng
phu'ong phdp xdc ^nh s6 lu'p'ng vd bd tri cdc lo mm
hpp ly tren gu'O'ng thi cong cong trinh ngam c6 y
nghTa thyc t l rit lo-n [1], [2], [3]
1 Ly thuylt chung v l cac phu'ang phap xac
djnh s6 lu'p'ng va bd tri cac Id min tren gu'O'ng
Cdng tdc xdc djnh so lu'p'ng vd b l tri cdc l§ min
trfen gu'O'ng thi cdng con^ trinh ngdm phai thyc
hi^n theo mOt so nguyen tdc ca ban nhu' sau [2];
• Dam bao dgt du'p'c hi#u qua cao nhdt cho
cdng tdc khoan nd min trong nh&ng dilu ki0n dja
ca hpc mdi tru'6'ng ddt dd eg thi, cho nhu-ng hinh
dang, kich thu'd'c mat cdt ngang cdng trinh ngim
eg t h i vdi nhOng thdng so ky thudt-cdng ngh0 nhit
djnh cua hp chieu khoan nd min;
• Dam bao h0 so SIJ dgng lo min "T\" dgt gid tri
Id-n nhit (gia tdng gdn bdng 1,0);
• Dam bao h# so thCFS tilt di^n V" d?t gid trj
nho nhit (giam xuong gan bdng 1,0);
• Dam bao mCpc dp dap vd' deu ddn cua dat
dd sau khi khoan n l min Dam bao mire dp vdng
xa nho nhit cua dat dd sau khi no min (dd sau khi
bj phd huy t$p trung chu yeu trong khu vyc g i n
gu'ang thi cdng cdng trinh ngam);
• Dam bao kha nang anh hu'dng it nhlt-td-i khoi
dd bao quanh cdng trinh ngam, cdc cdng trinh
GS.TS VO TRQNG HUNG
Truxmg Dai hgc Mo-Dia chat
ngim Idn can, mat dit, cdc cdng trinh xdy dyng tren mat ddt, ;
• Dam bao cdc Id min phai dupc bo tri deu ddn, hpp ly tren toan bO gu'ang thi cdng cdng trinh ngim;
• Mdi l5 min phai dam nhif m kha ndng phd huy vCing dit dd du'p'c "ky vpng" tuy thudc vdo ndng lye cua minh;
• Dam bao gu'ang thi cdng sau khi thyc hi?n cdng tdc khoan nd min cd dp sai l^ch It nhit so vd'i hinh dang, kich thu-d-c mat cdt ngang thi cdng cdng trinh ngam theo thiet ke;
• Khoang cdch giOa edc vdng l6 min "b" vd khoang cdch giCra hai lo min "c" trong eCjng mOt vdng (hang) Id min khdng du'p'c Idn han gid tn du'dng can toi thilu (du'dng can nho nhit) "W": b<W;c<W,
Rd rdng, nhirng yeu cdu phCrc tap va cin thilt tr^n ddy rit khd cd t h i dat du'p'c cung mpt luc trdn thyc t l vi rdt nhilu vin d l trong edng ngh0 khoan
no min van chu'a du'pc lam rd vd nghien CCPU thIu ddo Trong dd c6 vi0c xdc dinh s6 lu'p'ng vd b l ^i hpp
jy cdc lo min tren gu'ang tiii cdng cdng trinh ngim,
2 Nghien cu'u hoan thien phu>o=ng phap bd tri cac Id min hp'p ly tren gu'ang
Toan b0 ede Id min bo tri tren gu-ang thi cdng cdng trinh ngdm cd t h i du'p'c phdn chia ra thdnh ndm nhom Id min ca ban nhu- sau (H.I, H.2):
• Nhdm 1 - Nhdm cdc lo min dpt phd (nhdm A) Cdc l6 min nay c6 cdng dgng phd huy mpt phin khoi ddt dd tai khu vyc trung tdm va tao ndn mdt phdng ty
do thi> hai cho gu'ang thi cdng cdng trinh ngim Chung Joai cau tao eua nhdm lo min dpt phd se tiln hanh xdc djnh theo nh&ng chi dan d^c bi$t, ddc chung;
• Nhdm 2 - Nhdm cdc l6 min phd (nhdm B) Cde l6 min nay cd edng dung pha huy phan Idn khii dat
dd eho gu'ang thi cdng cdng trinh ngim Cdc l6 min phd du'pc thiet k l toy theo nhOng d$c dilm clu
Trang 2tgo-^2I_ KHOA HOC VA G O N G NGHE M P
clu trOc, tinh chit cua dat dd trgn gu'ang vd nhOng
dilu ld$n thi cdng khdc;
*:• Nhdm 3 - Nhdm cdc lo min bi§n (cdc l3 min
tao bidn) (nhdm C) Cdc l5 min nay cd cdng dgng
tao ndn bidn cdng trinh ngam theo dung ttiilt k l
Nhdm cdc l6 min ndy se nim cdch du-dng bidn hdng
va ndc mdt khoang tli Ihilu vd Idp lai hinh dang
du'dng bidn hdng vd ndc cua cdng trinh ngam eg thi;
*:* Nhdm 4 - Nhdm cdc l5 min nen (cdc l l min tao
nin) (nhdm D) Cdc l6 min ndy cd cdng dgng tao
nen nin cdng trinh ngim theo dOng thilt k l Nhdm
cdc l5 min ndy se ndm cdch du'dng bidn nin mOt
khoang tli thilu vd Idp lai hinh dang difdng bien nin
cua cdng trinh ngim eg thi;
*:* Nhdm 5 - Nhdm cdc l5 min ddc bi$t (nhdm E)
Cdc l5 min thudc nhdm ndy sO dgng d l khic phge
sy phdn b l khdng diu cua cac lo min d cdc nhdm l5
min b l tri canh nhau d l trdnh hipn hfpng dd qud cd
xuit hi$n do khoang cdch giOa cdc l6 min qud Idn
Cdc i l min ndy thu'dng xudt hi$n trong nh&ng cdng
trinh ngim cd hinh dang mdt elt ngang phCrc ta^ bidn cd gde canh, gdy khue, bien khdng tran Si
t i n tai cua ehung du'p'c thilt ke cho nh&ng cdn trinh ngim cd cac ddc dilm clu tao hinh hpc d | bi0t Trong nhilu tnrdng hp'p chiing ed t h i du-p ghdp vdo nhdm cdc l5 min phd Ngodi ra, tai ddy c
t h i t i n tai edc l6 min d l hinh thdnh rdnh tho^ nu'dc vd phgc vg cho cdc chCrc ndng khde Trong dd, nhdm edc l5 min d|t phd, nhdm cdc I min bien, nhdm cdc lo min nin vdn hdnh trong nhOn dilu kipn d$e bift hodc ed cdng dgng ddc bipt nhdr cdc Id min ddt phd vdn hdnh trong dilu ki$n chT c mOt mdt phdng ty do, cho ndn kit clu, kich thu-d
vd sa d l b l \r\ cua cde l6 min trong nhdm dOt ph
rit da dang; nhdm cdc l6 min bien, cdc l5 min ne dOng de tao nen mdt bidn, mdt nen cdng trtnh ngir theo dung thilt k l Vi vay, edc nhdm lo min ndy phi du'pc thiet k l vdi nhttng yeu cau ddc bipt d l cd th
sO dgng nhO-ng dilu kidn khdch quan nhdm thd mdn cdc ydu clu k$ thudt-edng ngh^ eg thi
H f Sa do nguyen tic bStricAcid min tr§n gwang thi c6ng cho m^t s6 cdng ttinh ngim c6 hlnh d^ng
m^t cit ngang kh^c nhau: a - M$t cit ngang hinh chO nh$t; b - M$t dt ngang hinh thang; c - M$t cSt ngang hinh vdm-tu^ng thing; d - M$t cit ngang hinh vdm tird'ng thing-vdm ngifQc; e - l\/l$t cit ngang hinh vom-tu^ng cong; g - M$t cit ngang hinh vom-tu^ng cong-vdm ngiK^c; h^- Chiiu cao thi cdng ICen nhit cOa cdng trinh ngim, m; ht, - Chiiu cao thi cdng cda tu^ng-v6m cdng'^hinh ngim m; h^ - Chiiu cao thi cdng cua vdm ngwqtc cdng trinh ngim, m; B^^ - Chiiu i^ng thi cdng l&n nhit (khiu <^) cOa cdng trinh ngim, m; B„ - Chiiu r^ng thi cdng idn nhat cOa nin cdng trinh ngim, m
^ 9 CdNG NGHIEP MO sd 6-2014
Trang 3KHOA HOC VA C O N G H B H E M 6 _ ^ ^
Thvc t l cho thiy: l i t kh6 c6 the thilt k l tdch
39ch, rS rdng cdc |6 min thu$c cdc nhdm |3 min
(hdc nhau tr6n gifcng Trong nhieu tru-d-ng hep,
bdc 15 min cua cdc nh6m khdc nhau c6 t h i (5an xen
nhau (it phCrc tap tuy theo dilu ki$n thi cong cdng
nguySn tic b l tri cdc |5 min trSn guang thi c6ng
m$t s i c6ng trtnh ngim cd hinh dang mdt cdt
ngang khdc nhau Cdc so do nguyen tdc b l tri cdc
i l min cho cdc guong thi cong cdng trinh ngim cd
hlnh d^ng m$t c i t ngang khdc nhau cho thay:
*:• So d l b l tri cdc io min tr&n gu'ang thi cdng phg
thudc rit idn vdo kich thudc, hinh dang cua m$t cit
ngang cong trinh ngim;
• Moi chung loai hinh dang mdt cit ngang cdng trinh ngam se ddi hoi mdt budc tiip can khdc nhau khi b l tri cdc vdng i l min tren guang thi cdng;
<* Neu nhdm cdc id min dot phd ^t/dng khdng phi,! thudc nhieu vdo hinh dang m$t cat ngang, thi cdc nhdm lo min khac se phai phu thupc rit idn vdo
So d l nguydn tic b l tri cdc l l min trdn guong thi
cdng cdng trinh ngim hinh vdm mdt tdm-tu-dng thing dCrng-nen phIng cd t h i the hi^n nhU" H.2 Ddy
Id phuong dn nghidn ci>u co so de phdt triln si> dung cho cdc giai phdp thilt ke mdt cit ngang khdc
H.2 Sa tfl nguyen tSc b6 tri cic l6 min Mn guong thi c6ng cong trinh ngim: a, - Khoang cich tir mi$ng to min bien din m$t biSn hong thi cong oiia cdng trinh ngam, m; a^ - Khoang cich tCt mi$ng IS min nSn Oen m$t biin thi cdng cua nSn cdng trinh ngim, m; b - Khoing cich giua hai vdng io min b6 tri C9nh nhau, m; c - Khoing cich hai l6 min canh nhau trong cung m0t vdng 16 min, m;^ h, - Chieu cao phSn thin-tudng cua cdng trinh ngim, m; h„ - ChiSu cao phin vdm cua cdng trinh ngam, m
TO H.2 Chung ta cd t h i nhan thiy: m i l i l min se
"idm vi^c" vd t?o nSn nh&ng "cdng ndng" n l min
dy kiln d l phd huy d i t dd cho ti>ng phin "didn tich
don vi" btang ung ddc tryng trdn guang thi cing
cing trinh ngim Tren H.2, H.3 gidi thilu cdc hinh
dang "di|n tich dan vi" khdc nhau ddc tru'ng cho
m l i mdt l l min khdc nhau b l tri trdn guang thi
cing cdng trinh ngim: i - Hlnh d?ng "di^n tich don
vi" cho tCmg i l min d|t phd thdng thudng (khi
chiing dui?c thilt k l tuang ty nhu cdc iS min phd)
vd cdc l l min phd tai phin thdn-tudng cing trinh
ngdm (H.3.1); il - Hlnh dang "dien tich dan vi" cho ti>ng io min phd tat phin vdm cdng trinh ngim (H.3.li); iii - Hinh dang "di^n tich dan vi" cho tung i l min bien hing tai phin thdn-tudng cdng trinh ngim (H.a.iil); IV - Hlnh dang "di$n tich dan vi" cho tCrng l l min nin tai phan nin cdng trinh ngim (H.S.iV); V -Hinh dang "di#n tich dan vj" cho i l min bien-nen tai gdc thip nhit cua phin thdn-tudng cdng trinh ngim (H.3.V): Vi - Hlnh dang "di|n tich don vi" cho tfrng io min phd tai phin chuyin tilp tir phin thdn-tydng sang phin vdm d n g trinh ngam (H.3.VI)
Trang 4^3_ KHOA HOC VA CONG NGHE MO
H.3 So do hlnh thinh cic hlnh d?ng "di^n tich don vj" khic nhiu
cho mgt s616 min dac tneng tr&n gtKfng thi cdng cdng trinh ngim
Rd rang, cac "dipn tich dan vj" cho mli mpt lo
min ddc trung khac nhau bd tri tren gu'ang thi cdng
cdng trinh ngim cd hinh dang, kich thu-dc rat khdc
nhau, Nhu" vdy, tuy theo vi tri eg the bo tri trdn
gu'ang, mdi Id min du'pc "ky vpng" se hodn thanh
nhipm vg phd vd dit da eho ti>ng phan "dipn tich
dan vj" ed hinh dang, kich thu-dc eg t h i rit khdc
nhau bao quanh chung (H.2, H-3)
3 Nghien ciru d l xudt nhu-ng djnh hu'dng ca
ban xac djnh s6 lu'p'ng va phu'ang phap bd tri
hp'p ly^ cdc Id min tren gu'ang
D l d l xuit nhOng djnh hu'dng tinh s i lu'png vd
xay dyng sa do bo tri cdc lo min trdn guang, diu
tien cin xdc ^nh tdng sd lu'p'ng l5 min "N" theo mdt
phu'ong phap ly thuylt-thyc nghipm ndo dd (vi dg
theo phuang phdp cua Pokrovski N.M [2]) Khi mdt
cdt ngang cdng trinh ngam cd dang doi xdng hinh
dinh hudng ea ban cho phuang phdp bo tri cdc lo
min trdn guang se dupc tiln hdnh nhu sau
Gid tri "didn tich dan vj" trung binh "Sdvtb" cho mli
Id min tren guang cd thi xdc djnh theo cdng thdc:
Tai ddy: Stc - Di$n tfch cua guang thi edng cdng
trinh ngim, m^; N - Tdng s i lup'ng l6 min tinh todn
cho todn bp guang thi cdng cdng trinh ngdm
Ngodi ra, gid tri "dipn tich dan vi" trung binh
"Sdvtb" dy kiln tinh cho mSi lo min tren guang cd
t h i xdc djnh bdng mli quan hp sau ddy:
Sdvtb=[(b).(c)], m^ (2)
Tgi day: b - Khoang each gida hai hang (vdng) l6
min eanh nhau, m; e - Khoang each giua hai l6 min
canh nhau trong ciJng mdt vdng l5 min, m
Cde gid tri "b", "c" phai dong thdi thoa mdn cdc
dieu ki$n sau ddy:
b<W; c^W (3)
Tai ddy: W - Gid tri dudng can nhd nhit (dudng
khdng nhd nhit) giua hai l5 min canh nhau trong
cCing m$t vdng l l min hode giua hai vdng l l min b l
tri cgnh nhau, m
Tu hai moi quan hp (2) va (3), chOng ta cd thi tim ra cdc mdi quan hd sau ddy:
S<,vtb<W'; (4)
(5)
(6)
Td (1) vd (4) rut ra dieu kipn:
Cde dilu kipn (4), (5), (6), (7) se giup ngudi thill
k l ed nhung djnh hudng ban dau de lya chpn s^
lupng l6 min trdn guang thi edng edng trinh ngim
Gid trj s i lup'ng ede vdng l5 min sa bd "msb" trer guang thi edng edng trinh ngdm (ehua k l vdng-hdng Id min nen) eo t h i xde dinh tu bilu thdc sai day (H.2):
' a s B H h - a i l
(7)
Tai ddy: Bdh - Khau dp (chilu rdng idn nhat) CUJ
cdng trinh ngdm, m; ai - Khoang cdch iin midng li
min bidn den mat bidn thi cdng cua tudng-hdnj cdng trinh ngim, m
So lu'ong cdc vdng l l min "m," cin phai cd trdi guong thi cdng cdng trinh ngim (chua k l vdng hang io min nin) cd t h i xdc dinh theo trinh ty sau:
• Lam trdn gid tri s i luong cac vdng Id min sc
bd "m,i," xdc ffinh theo bieu thirc (8) d i n gid tri si nguyen duang "m," g i n nhat:
m,=(m,b+A) (9) Tai ddy: A - Gid tri lam trdn b l sung vdo dai lypni
"m,b" sao cho ting (m^b+A) cd the dat duac gid t nguydn duang gan nhit;
•:• Cau tao cua 'm,^ gIm hai thdnh phin:
m,b=(PN+PTP) (10) Tai ddy: PN - Phin nguyen duang; PTP - Phd
thdp phan nhd hon 1,0; PTP<1,0;
•:• Khi phan sau d i u phdy (phdn thdp phSi
•PTP' cua dai lup'ng "m,b" idn han hodc bdng 0,
CANG NGHIEP me stf 6 - 2 0 1 4
Trang 5_ ^ ^
'•!/^TP>0,5) thi gid tri lam trdn b l sung "A" se duq^e
l^a chpn nhu sau:
A=PTP1<0,5vdi (PTP+PTP1)=1,0; _ (11)
• Trong trudng hyp ndy, s i luyng edc vdng l5
nin "mi" se dup'c xdc ^ n h theo cdng
thdc:-mi=(PN-H), vdng lo min; (12)
•??^ • Khi'phlBi«au ddu phly (phan thdp phdn) "PTP"
Hua gid trj dai-lu'p'ng "msb" nhd han 0,5 (PTP<0,5) thi
jid tri ldm trdn b l sung "A" se dupc lya chpn nhu sau:
A=(-PTP) vdi dilu kipn (PTP+A)=0,0; (13)
• Khi dd, s i lup'ng cde vdng lo min "mi" se
'%upc xdc djnh theo cdng thde:
mi=(PN), vdng 16 min (14)
I' So lup'ng cdc vong l l min " m / xac djnh theo
cdng thuc (14) phai thoa man dilu kien:
'• m,.[[^-^].0,4
i Trong trudng hpp nguyc lai, ting so lupng cdc
vdng lo min "mV thilt k l trdn guang thi cdng cdng
trinh ngam se phai xde djnh theo edng thuc (12)
Kit qua, ting s i lup'ng cde vdng l5 min "m" phai
ied trdn guang thi cdng edng trinh ngam (ke ca
vdng-hdng iS min nin) se dup'c xde 6\nh theo cdng thuc:
• m=(mi+1) vdng l l min (16)
Cull eCing, gid tn khoang cdch "b" giO-a ede
•• vdng l l min se xdc djnh theo cdng thde:
[ mi-0,5 J' (17)
So luyng vdng l6 min eho cde nhdm khac nhau
se dupc xdc djnh sa bd nhu sau:
• S l luyng vdng l5 min bidn "mb" duyc chpn
bdng mb=1 vdng lo min;
• s l lupng vdng lo min n i n "m^' dupc chpn
bang mn=1 vdng Id min;
• So lup'ng vdng Id min ddt phd "mdp": m(jp=1
vdng dudi dang mdt cap lo min ea ban b l tri theo
hai hang l6 min d l i xung nhau (H.2);
• s l luyng vdng Id min phd "mp";
mp=(mi-2), vdng lo min (18)
So lupng l l min "Nb" trong vdng min bien (khdng
k l hai Id min dau vd culi cua vdng lo min bidn thupc
ve vdng lo min nin) se dup'c xac t^nh theo cdng thuc:
Tai ddy: CDb - Ting chilu ddi cua vdng |5 min bien
tinh til vdng cdc Id min nen, m; Cb - Khoang cdch giOa
hai lo min bidn trong ciing mpt vdng l l min bien, m
s l luang lo min bien "Nb" xac djnh theo cong
thiic (18) dupc su dung trong phuang phdp khoan
nd min thong thudng Khi su dyng phyang phdp
khoan no min tao bidn, thudng s l iypng Id min tao
bidn "Ntb" phai tdng Idn do phai giam khoang cdch giua cdc l l min bien xuing bdng "ctb", Ctb<Cb Khi dd, bing gid tn "Ca" Trong trydng hpp ndy, s l lupng Id min tao bien "Nt" se dupc xdc i^nh theo cdng thuc:
So lupng id min " N / trong cde vdng min phd (khdng ke hai T6 min ddu vd cuoi cua vdng lo min phd thupc ve vdng l l min nen) se dupc xac djnh theo edng thue:
= l ( N p , ) - Z CD„ - 1 Id min (21) Tai ddy: Np,, - So lup'ng Id min trong vdng min phd thu "i" (khdng k l hai Id min diu vd eudi cua vdng lo min phd thudc v l vdng lo min nen); i - Thu ty cua tung-hdng lo min pha; i=1-fmp; CDp., - Tdng chilu dai cua vdng Id min phd thd "i" tinh tu vdng ede Id min nen, m; Cp., - Khoang cdch giua hai lo min phd trong cung mpt vdng lo min phd thd "i", m
Sd lupng Id min "Ndp" trong vdng min ddt phd thdng thudng (khdng k l hai lo min dau vd cuoi cua vdng lo min dpt phd thupc ve vdng lo min nen) se dupc xac djnh theo edng thdc:
^^'^'' ' • ,lomin (22)
N, ' d p '
Cdp
Tai day: CDdp - Chieu dai cua vdng Id min dpt pha thdng thudng tinh tu vdng edc l5 min nin, m; Cdp -Khoang each giua hai lo min trong cung mdt vdng l6 min dpt phd, m
s l lup'ng lo min "Nap" trong vdng lo min dot phd xac djnh theo cdng thuc (22) dupc su dung trong phuang phdp khoan n l min vdi cdu true cdc
Id min dpt pha thdng thudng, Khi sd dyng mpt so Chung loai cdu triie ddc bi^t khdc cho cdc l5 min ddt phd, thi s l lup'ng eua chdng thudng phai gia tang them vd bdng mpt gia tn "Ndp.t" phu hpp nao
dd Khi d6, nhdm lo min dpt phd dae bipt nay cd
t h i se xdm nhdp, "Idn sdu" vao khu vyc dipn tich guang thi edng do cdc vdng lo min phd dam nhipm, Dilu ndy se Idm suy giam so lupng cac lo min pha xuIng mpt gid trj "Npg" nao do
s l lupng Id min "Nn" trong vdng Id min nen se dupc xac djnh theo cdng thue:
Nn=(m+1), lomin, (23)
s l luyng lo min "Np" trong vdng lo min nin xac dinh theo cdng thue (23) dupc su dung trong phuang phdp khoan nd min vdi cau true cac lo min nin thdng thudng, Trong nhung trudng hop su dung phuang phdp khoan n l min tao^nen dde biej thi so luyng cua chung thudng phai gia tang them
Trang 6BL KHOA HOC VA C6NG NGHE MO
vd bdng mOt gid trj "Ntn" phi^ hpp ndo dd: ^1 ,
N„Jf?4^]+lj,llmln, , ,- ' • • (24)
Tai ddy: Cm -, Khodng cdph a^a b^i l l , min thudc
hdng (vdng) l l min nen'khi si> dgng phuang phdp
khoan n l min tao nen ddc bidt, m
S l lupng cdc lo min trong cdc nhom IS min
khdc nhau "Nb", "Nj,",-"Np", "Nap", "Nn", tuang i>ng
tinh theo cdc cing thyc (19),,(20), (21), (22), (24)
phai dypc Idm trdn d i n gid tri s l nguydn dyang
Idn han gin nhit
Culi cCing, ting s l cdc lo min tren guang thi
cdng "Ntc" trong phuang phdp khoan n l min thdng
thydng se dupc xdc dinh theo cdng thi>c:
Nic = (Nb+Np+Njp+N„+Ndb),llmin (25)
Tai ddy: Ndb - Cdc l l min ddc bidt
Ting s l cdc l l min trdn guang thi cdng "Ntc" khi
sir dyng kit clu nhdm l l min d$t phd ddc bidt s§
dupc xdc dinh theo cdng thi>c:
N|c=K+Np-Np.g+Nap,+^,+Nj,l5mln (26)
•Ting s l cdc l l min tren guang thi cdng "Nc" khi
sy dgng phyang phdp khoan n l min tao bidn, tao
nin ddc bidt vd kit clu nhdm lo min ddt phd ddc bidt:
Ntc=(Nib+V^.»+Ndp.i+Hn+Hib).l5min (27)
4 Nghien ciju d l xudt phu-ang phap b l tri
cdc Id min tren gyang
TCF kit qua nghidn cuu tren ddy, chung tdi d l
xuit phuang phdp b l tri cdc l l min tren guong thi
cdng cdng trinh ngam mat c i t ngang hinh
vdm-tudng thing dung (hinh H.2) theo cac budc sau:
• Bydc 1 - Xdc dinh ting s l lypng cdc l l min
"N" cho todn bd guong thi cdng cdng trinh ngim
trong nhD-ng didu ki$n k^ thudt-cdng n g h ^ a chit
eg t h i theo mdt phuang phdp ly thuylt ndo dd;
• Bydc 2 - Xdc dinh gid tri dudng can nhd nhit
(dydng khdng nho nhat) "W"; khoang cdch "c";
• Bydc 3 - Xdc dinh s l lypng cdc l l min cho
todn bp cdc nhdm l l min hoan todn binh ding nhu
nhau chya xdt din cdc dieu kipn Idm vide vd cdng
dgng cin dat dupc cua chung sau khi vdn hdnh,
sau khi dupc kich n l Gid tri ting s l lupng cdc l l
min "N" phai thda mdn dilu ki0n (7);
• Bydc 4 - Xdc dinh s l lypng cdc vdng-hdng lo
min "msb", "mi", "m" tren gyang thi cdng cdng trinh
ngim theo cdc cdng thCrc (8)4-(16);
• Bydc 5 - Xdc dinh gid tri khoang cdch "b"
giua cdc vdng l l min theo cdng thyc (17);
• Budc 6 - Xdc dinh s l lupng cdc vdng l l min
trdn gypng thi cdng cdng trinh ngim So lyp'ng
vdng |5 min phd "mp* xdc dinh theo d n g thCrc (18);
1 «,.Sydc 7.- Xdo dinh khoing cdch "Cp", chili ' ddi "CPb", s l lupng l l min "Np" trong vdng l l mli bidn trong phypng phdp khoan n l min thdnj thydng theo cdng thyc (19);
•:• Bydc 8 - Xdc dinh khoang cdch "c«,", s( lu'png l l min "N^," trong phuang phdp khoan ni min tao bidn theo cdng thijc (20);
•:• Bydc 9 - Xdc dinh cdc chilu ddi "CDp," ciia cdc vdng l l min phd thy "I";
•> Bydc 10 - Xdc dinh cdc khoang cdch "Cp.",
ting s l lupng cdc l6 min phd "Np" trong cdc vdng min phd (khdng k l cdc l l min d i u vd ciioi cua vdng
lo min phd thudc v l vdng l l min nin) theo cdng thyc (21);
.; Bydc 11 - Xdc dinh khoang cdch "cpp", so lupng l l min trong nhdm l l min ddt phd "Ndp" thee cdng thijc (22) hodc theo mdt nhdm l l min ddt phS
dd chpn eg the ndo dd;
•:• Budc 12 - Xdc dinh s l lypng l l min trong vdng l l min n i n "N„" khi sO dgng phyang phdp khoan n l min thdng thydng theo cing thuc (23);
• Bydc 13 - Xdc djnh khoang cdch "Cm"; s6-lypng l l min trong vdng l l min nen "Nm" khi sO dgng phuang phdp khoan n l min tao nin ddc bi$t theo cdng thuc (24);
•> Bydc 14 - Xdc dinh ting s l cdc l l min "NM" thudc nhdm cdc l l min ddc bi|t (cdc t l min thudc nhdm 5) tren gyang thi cdng cdng trinh ngim;
• Budc 15 - Xdc dinh tong s l cdc l l min trdn gyang thi cdng "NK" trong phyang phdp khoan no min thdng thudng theo cdng thuc (25);
•:• Budc 16 - Lya chpn vd thilt ke k i t cau nhdm min dpt phd ddc bi0t Xdc dinh s l lupng cdc l l min
"Nap," CLia nhdm min ddt phd dac bidt Xdc dinh phdn didn tich cua nhdm cdc l l min ddt phd ddc bipt "lln sdn" vdo phin dipn tich cua cdc l l min phd Xdc dinh s l lypng cdc l l min phd bi suy giam
"Npo" do bi nhdm cdc l l min ddt phd ddc bi|t
"chllm dgng" mit;
•:• Budc 17 - Xdc dinh ting s l cdc l l min trdn gyang thi cdng "NK" trong phuang phdp khoan nl min thdng thydng cd sy dgng kdt c l u nhdm min ddt phd ddc bipt theo cdng thiic (26);
^ •:• Budc 18 - Xdc dinh s l lypng cdc lo min tao nen "No," khi sy dgng phyang phdp khoan n l min tao nen ddc bidt;
•:• Budc 19 - Xdc dinh ting so cdc l l min trdn guong thi cdng "N^" khi sy dgng phyang phdp khoan n l min tao bidn, tao n i n dac bipt vd k i t clu nhdm l l min ddt phd dac bipt theo cdng thuc (27) Khi sy dgng cdc loai mdt cdt ngang cdng trinh ngim khdc hinh vdm-tydng thing flCrng (hlnh H.I a, 1 b, 1 d, 1 e, 1 g), ngydi thilt kl^phli tiln hdnh
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CdNGNBHIEPM0Sd6-2014